Oh god Cazboldy, where to start.
It would be lovely if veal were produced as a byproduct. Realy, I'd be overjoyed with that outcome.
This is as best as I understand, may need bits correcting:
The real outcome is the calves are separated after 2-3 days (when colostrum finishes). Then they drink formula, basically, part cow's milk part cheaper subs. The cows and their babies pine loudly for each other. Somebody on MN once said her relative... brother? switched from dairy to beef farming because of animal welfare issues (although beef production increasingly all indoors & industrialised, too).
That's the girls who get to drink cow formula.
The boys are bolted (killed) overwhelmingly, at about 36 hours old.
Most British dairy cows are now Holsteins, an American breed developed to be intensive milk producers (factory style production).
Their general well-being is not high due to the intensive pressure on them (milk prices are on the floor, , and many British farmers are quite uncomfortable with the high rates of mastitis & other health problems they tend to develop.
Holstein male calves are especially unsuitable for the veal market, hence why they get bolted.
Actually, following mid 1990s protests over live veal exports AND the industry shift to Holsteins, there's no market for male calves turned into veal (British people don't much like veal). So most, even those from Friesan cows and other breeds suited to make veal, are just bolted soon after birth, because no market for the males exists.
As for the lives of Dairy cows, it's increasingly common in the global market for dairy cows to live their whole lives in doors, fed overwhelmingly on grain. This gets high yields out of Holsteins. It is usually judged to be a very inefficient (environmentally unsustainable) practice, using arable land that could grow people food to feed cows to make milk (even more inefficient if it's to make beef, mind). The overmilked cows have high rates of infection (mastitis & other). And relatively short lives. They aren't suited to be eaten at end of those lives, so just killed & next milk-making unit rolled in...
See in ideal world we'd feed cows on grass (cheap, inedible to us, grows fast) in rotation with other crops, so cows fertilise the land inbetween crops and makes an inedible grass into something we like (milk + beef). And get to live in nice herds with other cows and their relatives In reality cows live most their lives in same sex groups, eating grain food, in stalls. I once read that cows who graze on grass produce a lot of Omega type oils in their milk + meat, too.
The Archers (Radio 4) has covered the veal calf problem in last year & is developing a storyline about mega-indoor-dairy production.